1 Field of the Invention
The present invention relates to a network system available for simultaneous connections of plural pieces of terminal equipment such as portable communication terminals, advanced equipment in the system, a method of using functions of another piece of equipment, and a storage medium.
2 Description of the Related Art
Conventionally, in the area of portable communication terminal devices, voice-only telephones or advanced terminals capable of exchanging textual information in addition to voice information have become commercially practical. Further, image exchangeable terminals such as video telephones and personal computers are now on the market. On the other hand, in the area of display devices, compact display devices with excellent portability and low power consumption such as liquid crystal displays are proceeding toward practical utilization. In addition, display devices for possible adoption into portable terminals have also been studied and become commercially practical.
However, when combining a portable terminal with a display device, a tradeoff will have to be made between portability of a compact terminal and visibility of a larger display screen. In other words, providing a large, high-definition display device increases the size of the portable terminal and hence reduces its portability. On the other hand, if high priority is given to portability, the screen size has to be reduced, which makes it difficult to display images with high definition on a large screen.
To solve the above-mentioned problem, a video telephone system has been proposed, in which a display device is provided on a desktop-type public terminal accessible from portable telephones or terminals so that a large, easy-to-see display screen can be obtained with maintaining the portability of portable terminals. This proposal, however, needs to prepare public terminals and portable terminals, both of which have a dedicated interface.
On the other hand, as digital-network penetration increases in telecommunications, various kinds of additional services are now available such as to establish another connection with maintaining current connection between communication partners. Even through an existing analog network, plural connections are possible by multiplexing via a modem or the like.
For example, U.S. Pat. No. 6,195,545 (Japanese Patent Laid-Open Application No. 11-331957) discloses a call processing method in which a proximity-based temporary association is established, within a system switch, between a terminal and at least one other terminal. While the terminal is associated with the other terminal, the terminal user can utilize the functions of the other terminal.
The call processing method according to U.S. Pat. No. 6,195,545 (Japanese Patent Laid-Open Application No. 11-331957) can assume such utilization that a portable terminal accesses a display facility of another terminal. This utilization can solve the above-mentioned problem. Since U.S. Pat. No. 6,195,545 discloses call processing within a system switch, it is adopted to a local-area network, but its application to a wide-area network requires the installation of new or additional system switches or addition of functions to the system switch, resulting in the need to change the entire network.